In recent years, fuel cells have been noted as portable power supplies. For example, as disclosed in Japanese Patent Laid-Open No. 2003-115308 (Patent document 1), a pressure regulating mechanism including the following components is known: a first pressure regulating chamber and second pressure regulating chamber separated by a partition; and a third pressure regulation chamber separated from the second pressure regulation chamber by another partition; a pressure regulating wall defining the third pressure regulation chamber; and a supporting shaft which is connected to this pressure regulation wall and penetrates the partitions, and can move forward and backward. This pressure regulating mechanism has one connecting hole for an external system in communication with the first pressure regulating chamber, and another connecting hole for the external system in communication with the second pressure regulating chamber. In this pressure regulating mechanism, a fluid (gas) can flow into one of the connecting holes and discharge from anther.
On the other hand, notebook personal computers (hereinafter called notebook PCs) including such a fuel cell are known as portable electronic equipments (Patent document 2: Japanese Patent Laid-Open No. 2004-179149; Patent document 3 Japanese Patent Laid-Open No. 2002-49440). These notebook PCs include a main unit on which keys for inputting characters are arranged, and a cover member which is pivotally hinged to the main unit and can cover the main unit. A fuel cartridge for supplying fuel to a fuel cell is mounted to the outer edge of the front side of the cover member, namely, to the outer edge opposite the hinge portion. The fuel is supplied from this fuel cartridge to a panel type fuel cell. The fuel cell is provided to the rear of a display liquid crystal panel of the cover member. A fuel cell disclosed in the patent document 2 is a direct methanol fuel cell for directly supplying methanol to a fuel electrode of a fuel cell. The direct methanol fuel cell does not need a reformer, so that a structure of the system can be simple.
Therefore, in the case where a notebook PC is carried somewhere other than home, when an additional fuel cartridge is carried, a used fuel cartridge is exchanged to the new one, and thus electronic equipment such as a notebook PC can be used continuously without worrying running out of fuel.
In order to install a pressure regulating mechanism and fuel cartridge disclosed in the patent document 1 to a compact electronic equipment such as a notebook PC disclosed in the patent document 2, the pressure regulating mechanism and fuel cartridge need to be compact. The pressure regulating mechanism disclosed in the patent document 1 has only one outer connecting hole into which a fuel flows, and can mount one fuel cartridge. Since a usable duration of electronic equipment is determined in accordance with a supply amount of a fuel when the same type of fuel is supplied, a capacity of the fuel cartridge is preferably large. When electronic equipment such as a notebook PC is carried around, and used somewhere other than home, an interchangeable fuel cartridge may be carried around. Therefore, the fuel cartridge is preferably compact. In recent years, such contrary requests need to be satisfied. For example, when two fuel cartridges are mounted to increase a fuel capacity, a pressure regulating mechanism for two fuel cartridges becomes large. Therefore, it is difficult to install the pressure regulating mechanism in a small space such as a notebook PC.
The fuel cartridge disclosed in the patent document 3 has a full length of the outer edge of the cover member. The whole fuel cartridge projects from the outer edge. The fuel cartridge disclosed in the patent document 2 is placed inside the outer edge of the cover member along the outer edge of the cover member.
The fuel cartridges disclosed in the patent documents 2, 3 are large compared to a size of a notebook PC, and inconvenient to carry. When the fuel cartridges are made compact to be convenient to carry, a duration of the power supply is shortened. Therefore, there is not so much benefit to use fuel cells as power supplies.
The above two related arts (patent documents 2, 3) are fuel supply systems where fuel is supplied to a fuel cell by use of a weight of the fuel itself. Therefore, in order to supply fuel to a panel type fuel cell placed to the cover member, the fuel cell is necessarily placed to the upper edge of the cover member. As a result, because of the heavy fuel cell, the stability of the notebook PC is decreased when the PC is used.
In view of such problems, the present invention is to provide a compact pressure regulator for a fuel cell, the regulator being able to incorporate at least two fuel cells and to be installed in a small space.
Furthermore, the present invention is to provide a fuel supply system for a fuel cell and a fuel cartridge used in the system, wherein an electronic equipment using a fuel cell can be used for long time, while using a compact fuel cartridge convenient to carry.
Further, the present invention is to provide a fuel supply system for a fuel cell and a fuel cartridge used in the system, wherein when the fuel supply system and the fuel cartridge are installed in electronic equipment, the stability of the electronic equipment can be maintained and the fuel supply system and fuel cartridge do not occupy so much space.